Flax Growth Modelling

Logistic model reveals early sowing as key to maximizing flax (Linum usitatissimum L.) vegetative growth under subtropical conditions

🌱 Logistic Model Reveals Early Sowing as Key to Maximizing Flax Vegetative Growth

A comprehensive nonlinear growth analysis of Linum usitatissimum L. under subtropical conditions using logistic models, degree-day accumulation, and derivative-based critical point estimation.

📍 UFSC – Brazil 🔬 Agronomy Journal 📦 R · ggplot2 · nls 📅 2025

About the study

Flax (Linum usitatissimum L.) is a dual-purpose crop of increasing interest in subtropical regions. Understanding the vegetative growth dynamics in response to thermal time is essential for optimizing sowing windows and maximizing fibre and seed production.

This study fitted three-parameter logistic models to leaf area, plant height, and leaf number as a function of accumulated growing degree-days (GDD), evaluated across two sowing dates (E1 and E2) and two cultivars (Dourado and Monarca) in Florianópolis, Santa Catarina, Brazil.

Key insights were derived by analysing the first and second derivatives of the fitted curves to identify inflection points (maximum growth rate) and critical acceleration/deceleration thresholds.

Analysis pipeline

🌡️ ### Climate Data Daily temperature and rainfall records processed to compute accumulated GDD for each sowing season.

🍃 ### Leaf Area Logistic model fit to leaf area per plant (cm² plant⁻¹) with ANOVA on estimated parameters.

📏 ### Plant Height Logistic model fit to plant height (cm) and derivative-based identification of maximum elongation rate.

🔢 ### Leaf Number Logistic model fit to cumulative leaf count per plant with critical point analysis.

📊 ### Correlations Pearson correlations among growth variables across measurement dates and treatments.

📐 ### Logistic Model \[y = \frac{\beta_1}{1 + e^{\beta_3(\beta_2 - x)}}\] where x = GDD, β₁ = asymptote, β₂ = inflection point, β₃ = growth rate.

Citation

Authors. (2025). Logistic model reveals early sowing as key to maximizing flax (Linum usitatissimum L.) vegetative growth under subtropical conditions. Agronomy Journal. doi: pending

🚀 Start the analysis 👥 About the team Source code